Global trends toward achieving net-zero emissions raise awareness of sustainability in construction. Energy retrofitting construction is gaining high recognition as a competent option to mitigate energy consumption during the use period, which is found to be a vast contributor to carbon emissions. However, considering that many older buildings are challenged by disasters, such as structural degradation and increased earthquake risks, structural strengthening construction is also in high demand. A practical solution is seismic retrofitting, which can improve the resistance of buildings to disasters, prolong their lifespan, and improve the resilience of the community. Therefore, it is essential to take both seismic and energy retrofitting into account. Several existing Building Information Modeling tools for carbon emission calculations are applicable to energy retrofitting but lack support for seismic retrofit or combined retrofitting options. Furthermore, they often focus on the operational stage and neglect the construction phase of existing buildings, which involves the addition of new structural or architectural components and requires processes of partial demolition of the surrounding elements, waste disposal, and others. A novel BIM-based framework for assessing carbon footprints has been developed to overcome these limitations using Autodesk Revit and energy simulation software. This framework goes beyond estimating the operational and embodied carbon emissions; it also considers the construction cost associated with the different integration of energy and seismic retrofit strategies. A reinforced concrete school building is applied as a case study to illustrate its capabilities. The life cycle assessment encompasses the boundary of the cradle-to-grave system, including the product, construction process, operational and end-of-life stages. The proposed framework enables a comparison of various energy retrofit options and commonly used seismic retrofit strategies. Ultimately, satisfactory design alternatives, in terms of sustainability and cost-effectiveness, are facilitated for the design decision-making process for energy and seismic retrofit construction projects.